In recent years, a critical need has emerged for safe and reliable methods of extracting and testing blood samples from patients, particularly as a result of the AIDS epidemic. As a result, automatic skin pricking lancet devices have been developed to replace the traditional needle in some applications. These lancet devices generally have an extractable spring loaded blade or dart for pricking the patient's skin upon the pressing of a button, lever mechanism or switch. The blade then automatically retracts back into the device housing thereby preventing the attending physician or nurse from being pricked by the bloody blade. A sample of blood is then extracted from the patient, often by using a small pipette which draws the blood sample by capillary action. Or, the patient may drop a blood sample into a test tube. In any event, the auto-pricking device is designed for a one time use such that the blade, once extracted and retracted, cannot be extracted a second time thereby preventing accidental skin incisions. After each use, the device is usually discarded.
Examples of such prior art auto-pricking devices are found in U.S. Pat. No. 5,133,730 to Biro et al., entitled "Disposable-Retractable Finger Stick Device", and assigned to International Technidyne Corporation, the assignee herein. This patent teaches a disposable auto-pricking device having a lever arm such that when the device is pressed against the patient's skin and the lever arm depressed, a blade rapidly incises the patient's skin at a predetermined depth, and then safely retracts back into the device. This invention, however, is not directed towards efficiently collecting a sample of the patient's blood for further analysis.
U.S. Pat. No. 4,959,196 to C. Moisson, entitled "Device for Blood Sampling and Analysis" discloses an auto-pricking device integral with an assembly for testing the blood sampled to evaluate desired concentrations of substances therein. After the patient's finger is pricked with this device, the patient deposits a drop of blood onto a strip with a reactive agent. The blood is then automatically tested by means of a reflectometer integral with the assembly. While this device thus enables a particular blood test to be quickly performed in a safe manner, it lacks means built into the unit to temporarily store a blood sample to allow the blood sample to be transferred to another, perhaps more sophisticated blood testing apparatus.
There exists in the prior art, a myriad of apparatuses for performing different tests on blood samples. One such apparatus is found in co-pending U.S. patent application Ser. No. 08/359,923, entitled "Portable Prothrombin Time Test Apparatus and Associated Method of Performing a Prothrombin Time Test", by Gavin et al., and assigned to International Technidyne Corporation, the assignee herein. The apparatus disclosed in this patent performs a prothrombin time (PT) test on a sample of blood. Attachable to the apparatus and necessary for its operation is a disposable cuvette having an opening within which a sample of blood is placed. The blood sample is then tested by the apparatus without contacting the blood sample, whereupon the cuvette is disposed of. The preferred testing method requires that the cuvette be attached to the apparatus prior to the blood sample being placed therein. Thus a blood sample could be transferred directly from a patient to the cuvette if the patient is in close proximity to the apparatus. This is not always practical, however, inasmuch as the apparatus may desirably be located in a room separated from the patient. Alternatively, one could utilize an auto-pricking device to create the skin incision, collect the patient's blood sample in a test tube or pipette, and then transfer the blood to the cuvette. The disadvantage with this latter technique is that the treating physician often prefers to create the incision with the auto-pricking device using his right hand while holding the patient's finger with his left hand (or vice versa), then place the auto-pricking device down while picking up the test tube or pipette with his right hand to gather the blood sample. Similarly, a patient using an auto-pricking device in conjunction with a test tube to take his or her own blood sample would also have to separately retrieve the test tube after performing the incision.
Another option for the physician is to hold the auto-pricking device in his right hand while simultaneously holding the test tube or pipette in his left hand during the incising procedure. In this case, the physician must rely on the patient to hold his finger steady or otherwise hold the finger stationary, which is not always practical.
In any case, the pipette or test tubes are stored separately from the auto-pricker which is a significant drawback in terms of logistics.
Thus there is a need for a blood sampling device including an auto-pricking device integrated with a reservoir to enable a physician or patient to safely collect a blood sample without having to retrieve a separate test tube or other blood storage means. There is also a need for the reservoir of such a blood sampling device to have a funnel-like shape with two openings for enabling clean collection of the blood sample and efficient transferring of the sample to a blood analysis apparatus.
It is an object of the present invention to provide a blood sampling apparatus that fulfills the aforementioned needs and overcomes the drawbacks of the prior art.
There is a further need to provide such a blood sampling device that has a substantially flat platform which allows the device to be readily placed at rest after the blood sampling operation. This feature would enable the incision to be given prompt attention after the blood sample is taken, particularly for a patient taking his or her own blood sample.